General Description
The MAX9730 features a mono Class G power amplifier
with an integrated inverting charge-pump power supply.
The charge pump can supply up to 500mA of peak out-
put current over a 2.7VDC to 5.5VDC supply voltage
range, guaranteeing up to 2.4W output power into an
8Ωload. The 2.4W output power allows for transient
audio content to remain unclipped as the battery rail col-
lapses over time.
The MAX9730 maximizes battery life by offering high-
performance efficiency. Maxim’s proprietary output
stage provides efficiency levels greater than Class AB
devices without the EMI penalties commonly associat-
ed with Class D amplifiers. High efficiency allows the
MAX9730 to be packaged in a UCSP™ package with-
out derating the output power handling capability.
The device utilizes fully differential inputs and outputs,
comprehensive click-and-pop suppression, shutdown
control, and soft-start circuitry. The MAX9730 is fully
specified over the -40°C to +85°C extended tempera-
ture range and is available in ultra-small, lead-free,
20-bump UCSP (2mm x 2.5mm) and 28-pin TQFN
(4mm x 4mm) packages.
Features
o2.7V to 5.5V Operation
oIntegrated Charge-Pump Power Supply
o63% Efficiency (VCC = 5V, POUT = 1W)
o2.4W Output Power into 8Ωat VCC = 3.3V
oUp to 2.4W Instantaneous Output Power into 8Ω
oClickless/Popless Operation
oSmall Thermally Efficient Packages
2mm x 2.5mm 20-Bump UCSP
4mm x 4mm 28-Pin TQFN
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
________________________________________________________________
Maxim Integrated Products
1
PART TEMP RANGE PIN-
PACKAGE
PKG
CODE
MAX9730EBP+T* -40°C to +85°C 20 UCSP-20 B20-7
MAX9730ETI -40°C to +85°C 28 TQFN-EP** T2844-1
Ordering Information
MAX9730
+
IN+
FB+
RIN+
CPVDD
2.7V TO 5.5V
RIN-
CIN
CIN
IN-
FB-
OUT+
OUT-
-
CLASS G
OUTPUT
STAGE
CHARGE
PUMP
RFB+
RFB-
VCC
CPGNDGND
Simplified Block Diagram
19-0701; Rev 0; 12/06
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
MP3 Players
Personal Media Players
Handheld Gaming
Consoles
Cell Phones
Smartphones
Notebook Computers
Applications
Typical Application Circuit/Functional Diagram and Pin
Configurations appear at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
+
Denotes lead-free package.
*
Future product—contact factory for availability.
**
EP = Exposed pad.
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 =
10µF; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX, unless other-
wise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
(Voltages with respect to GND.)
VCC, CPVDD .............................................................-0.3V to +6V
PVSS, SVSS ...............................................................-6V to +0.3V
CPGND..................................................................-0.3V to +0.3V
OUT+, OUT-...................................(SVSS - 0.3V) to (VCC + 0.3V)
IN+, IN-, FB+, FB- ......................................-0.3V to (VCC + 0.3V)
C1N..........................................(PVSS - 0.3V) to (CPGND + 0.3V)
C1P.......................................(CPGND - 0.3V) to (CPVDD + 0.3V)
FS, SHDN ...................................................-0.3V to (VCC + 0.3V)
Continuous Current Into/Out of
OUT+, OUT-, VCC, GND, SVSS .....................................800mA
CPVDD, CPGND, C1P, C1N, PVSS.................................800mA
Any Other Pin ..................................................................20mA
Duration of OUT+, OUT- Short Circuit to
VCC, GND, CPVDD, CPGND ..................................Continuous
Continuous Power Dissipation (TA= +70°C)
20-Bump UCSP (derate 10.3mW/°C above +70°C) .....827mW
28-Pin TQFN (derate 20.8mW/°C above +70°C) ........1667mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................+300°C
Bump Temperature (soldering) Reflow............................+235°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
GENERAL
Supply Voltage Range VCC Inferred from PSRR test 2.7 5.5 V
Quiescent Current ICC 812mA
Chip Power Dissipation PDISS VOUT = 2.8VRMS, f = 1kHz, RL = 8Ω0.9 W
Shutdown Current ISHDN SHDN = GND 0.3 5 µA
Turn-On Time tON Time from shutdown or power-on to full
operation 50 ms
Input DC Bias Voltage VBIAS IN_ inputs 1.1 1.24 1.4 V
ILOAD = 0mA (slow mode) 55 83 110
Charge-Pump Oscillator
Frequency (Slow Mode) fOSC ILOAD > 100mA (normal mode) 230 330 430 kHz
Maximum Capacitive Load CL200 pF
VIH 1.4
SHDN Input Threshold (Note 3) VIL 0.4 V
SHDN Input Leakage Current ±1 µA
SPEAKER AMPLIFIER
TA = +25°C ±3 ±15
Output Offset Voltage VOS TMIN ≤ TA ≤ TMAX ±20 mV
Common-Mode Rejection Ratio CMRR fIN = 1kHz (Note 4) 68 dB
Click-and-Pop Level VCP
Peak voltage into/out of shutdown
A-weighted, 32 samples per second
(Notes 5, 6)
-52 dBV
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 =
10µF; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX, unless other-
wise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
Note 1: All devices are 100% production tested at room temperature. All temperature limits are guaranteed by design.
Note 2: Testing performed with resistive and inductive loads to simulate an actual speaker load. For dynamic speakers,
RL= 8Ω, 68µH.
Note 3: Designed for 1.8V logic.
Note 4: RIN_ and RFB_ have 0.5% tolerance.
Note 5: Amplifier inputs AC-coupled to GND.
Note 6: Testing performed at room temperature with 8Ωresistive load in series with 68µH inductive load connected across BTL
output for speaker amplifier. Mode transitions are controlled by SHDN. VCP is the peak output transient expressed in dBV.
Note 7: Voltage gain is defined as: [VOUT+ - VOUT-] / [VIN+ - VIN-].
Note 8: Mode A tone burst tested at full amplitude for one cycle and half amplitude for nine cycles. Mode B tone burst tested at
full amplitude for three cycles and half amplitude for seven cycles. Full amplitude is defined as 1% THD+N at full battery
(VCC = 4.2V).
Electrical Characteristics
table targets must be met at THD+N = 1% for one cycle (Mode A) and THD+N <
5% for three cycles (Mode B).
Note 9: Dynamic range is calculated by measuring the RMS voltage difference between a -60dBFS output signal and the noise
floor, then adding 60dB. Full scale is defined as the output signal needed to achieve 1% THD+N.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Voltage Gain AV(Notes 4, 7) 11.5 12 12.5 dB
VCC = 5V 2.4
VCC = 4.2V 1.67
VCC = 3.6V 1.25
Continuous Output Power POUT THD+N = 1%, f = 1kHz,
RL = 8Ω
VCC = 3.0V 0.8
VRMS
VCC = 5V 7.1
VCC = 4.2V 5.9
VCC = 3.6V 5.1
f = 1kHz, 1% THD+N,
ZL = 1µF + 10Ω
VCC = 3.0V 4.2
VCC = 5V 6.5
VCC = 4.2V 5.4
VCC = 3.6V 4.7
Output Voltage VOUT
f = 10kHz, 1% THD+N,
ZL = 1µF + 10Ω, no
load
VCC = 3.0V 3.8
W
VCC = 2.7V to 5.5V 63 77
f = 217Hz, 200mVP-P ripple 77
f = 1kHz, 200mVP-P ripple 77
Power-Supply Rejection Ratio
(Note 4) PSRR
f = 20kHz, 200mVP-P ripple 58
dB
RL = 8Ω, VOUT = 1kHz / 400mW 0.007
Total Harmonic Distortion Plus
Noise THD+N RL = 8Ω, VOUT = 1kHz / 1W 0.12 %
Signal-to-Noise Ratio SNR VOUT = 0.5W, inputs to GND by C1N,
A-weighted 95 dB
22Hz to 22kHz 96
Dynamic Range DR (Note 9) A-weighted 99 dB
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 =
10µF, RL= 8Ω; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX9730 toc01
FREQUENCY (kHz)
THD+N (%)
1010.1
0.01
0.1
1
10
0.001
0.01 100
VCC = 3V
POUT = 0.69W
POUT = 0.33W
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX9730 toc02
FREQUENCY (kHz)
THD+N (%)
1010.1
0.01
0.1
1
10
0.001
0.01 100
VCC = 3.6V
POUT = 0.37W
POUT = 0.93W
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX9730 toc03
FREQUENCY (kHz)
THD+N (%)
1010.1
0.01
0.1
1
10
0.001
0.01 100
VCC = 5V
POUT = 0.83W
POUT = 2.08W
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX9730 toc04
OUTPUT POWER (W)
THD+N (%)
1.00.5
0.01
0.1
1
10
0.001
0 1.5
VCC = 3V
fIN = 1kHz
fIN = 10kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX9730 toc05
OUTPUT POWER (W)
THD+N (%)
1.51.00.5
0.01
0.1
1
10
0.001
0 2.0
VCC = 3.6V
fIN = 1kHz
fIN = 10kHz
fIN = 20Hz
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT POWER
MAX9730 toc06
OUTPUT POWER (W)
THD+N (%)
3.02.52.01.51.00.5
0.01
0.1
1
10
0.001
03.5
fIN = 20Hz
fIN = 10kHz
fIN = 1kHz
VCC = 5V
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX9730 toc07
FREQUENCY (kHz)
PSRR (dB)
1010.1
-80
-70
-60
-50
-40
-30
-20
-10
0
-90
0.01 100
VRIPPLE = 200mVP-P
POWER EFFICIENCY
vs. OUTPUT POWER
MAX9730 toc08
OUTPUT POWER (W)
EFFICIENCY (%)
1.00.5
10
20
30
40
50
60
70
0
01.5
VCC = 3V
fIN = 1kHz
POWER EFFICIENCY
vs. OUTPUT POWER
MAX9730 toc09
OUTPUT POWER (W)
EFFICIENCY (%)
1.00.5
10
20
30
40
50
60
70
0
01.5
VCC = 3.6V
fIN = 1kHz
Typical Operating Characteristics (continued)
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 =
10µF, RL= 8Ω; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
_______________________________________________________________________________________
5
POWER EFFICIENCY
vs. OUTPUT POWER
MAX9730 toc10
OUTPUT POWER (W)
EFFICIENCY (%)
21
10
20
30
40
50
60
70
0
03
VCC = 5V
fIN = 1kHz
STARTUP WAVEFORM
MAX9730 toc11
10ms/div
SHDN
5V/div
OUT+ - OUT-
500mV/div
SHUTDOWN WAVEFORM
MAX9730 toc12
10ms/div
SHDN
5V/div
OUT+ - OUT-
500mV/div
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9730 toc13
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.55.04.54.03.53.0
2
4
6
8
10
12
0
2.5 6.0
SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE
MAX9730 toc14
SUPPLY VOLTAGE (V)
SHUTDOWN CURRENT (μA)
5.55.04.0 4.53.53.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
2.5 6.0
OUTPUT POWER
vs. SUPPLY VOLTAGE
MAX9730 toc15
SUPPLY VOLTAGE (V)
OUTPUT POWER (W)
5.55.03.0 3.5 4.0 4.5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0
2.5 6.0
10% THD+N
1% THD+N
fIN = 1kHz
OUTPUT POWER
vs. LOAD RESISTANCE
MAX9730 toc16
LOAD RESISTANCE (Ω)
OUTPUT POWER (W)
80604020
0.5
1.0
1.5
2.0
2.5
3.0
0
0100
VCC = 5V
VCC = 3.6V
fIN = 1kHz
POUT AT 1% THD+N
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
6 _______________________________________________________________________________________
6 _______________________________________________________________________________________
CLASS G OUTPUT WAVEFORM
MAX9730 toc17
200μs/div
OUT+ - OUT-
10V/div
OUT-
5V/div
OUT+
5V/div
1% THD+N
FREQUENCY RESPONSE
MAX9730 toc18
FREQUENCY (Hz)
GAIN (dB)
10k1k100
2
4
6
8
10
12
14
16
18
20
0
10 100k
POUT = 1W
Pin Description
Typical Operating Characteristics (continued)
(VCC = CPVDD = SHDN = 3.6V, GND = CPGND = 0V, RIN+ = RIN- = 10kΩ, RFB+ = RFB- = 10kΩ, RFS = 100kΩ, C1 = 4.7µF, C2 =
10µF, RL= 8Ω; speaker load resistors (RL) are terminated between OUT+ and OUT-, unless otherwise stated; TA= TMIN to TMAX,
unless otherwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)
PIN
TQFN UCSP NAME FUNCTION
1B2SHDN Shutdown
2, 5, 6, 8, 11, 17,
19, 23, 25, 28 — N.C. No Connection. No internal connection.
3 A2 C1P Charge-Pump Flying Capacitor, Positive Terminal. Connect a 4.7µF
capacitor between C1P and C1N.
4 A3 CPVDD Charge-Pump Positive Supply
7 A4 FB- Negative Amplifier Feedback
9 A5 IN- Negative Amplifier Input
10 B5 IN+ Positive Amplifier Input
12 B4 FB+ Positive Amplifier Feedback
13 C5 FS Charge-Pump Frequency Set. Connect a 100kΩ resistor from FS to
GND to set the charge-pump switching frequency.
14, 22 D1, D5 VCC Supply Voltage. Bypass with a 10µF capacitor to GND.
15, 21 C2, C4 SVSS Amplifier Negative Power Supply. Connect to PVSS.
16 D4 OUT- Negative Amplifier Output
18 D3 GND Ground
20 D2 OUT+ Positive Amplifier Output
24 C1 PVSS Charge-Pump Output. Connect a 10µF capacitor between PVSS and
CPGND.
26 B1 C1N Charge-Pump Flying Capacitor, Negative Terminal. Connect a 4.7µF
capacitor between C1N and C1P.
27 A1 CPGND Charge-Pump Ground. Connect to GND.
EP — EP Exposed Pad. Connect the TQFN EP to GND.
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
_______________________________________________________________________________________ 7
ON
IN1 IN1
P
N1
N2
IP
ON
OFF
RL
VCC
SVSS
LOW SUPPLY RANGE OPERATION
IP = IN1
ON
IN2 IN2
P
N1
N2
IP
ON
ON
RL
VCC
BTL CLASS G SUPPLY TRANSITION
SVSS
SUPPLY TRANSITION
IP = IN1 + IN2
ON P
N1
N2
IP
OFF
ON
RL
VCC
SVSS
HIGH SUPPLY RANGE OPERATION
IP = IN2
Detailed Description
The MAX9730 Class G power amplifier with inverting
charge pump is the latest in linear amplifier technolo-
gy. The Class G output stage offers the performance
of a Class AB amplifier while increasing efficiency to
extend battery life. The integrated inverting charge
pump generates a negative supply capable of deliver-
ing up to 500mA.
The Class G output stage and the inverting charge pump
allow the MAX9730 to deliver an output power that is up
to four times greater than a traditional single-supply linear
amplifier. This allows the MAX9730 to maintain 0.8W into
an 8Ωload as the battery rail collapses.
Class G Operation and Efficiency
The MAX9730 Class G amplifier is a linear amplifier that
operates within a low (VCC to GND) and high (VCC to
SVSS) supply range. Figure 1 illustrates the transition
from the low to high supply range. For small signals,
the device operates within the lower (VCC to GND) sup-
ply range. In this range, the operation of the device is
identical to a traditional single-supply Class AB amplifi-
er where:
ILOAD = IN1
As the output signal increases, so a wider supply is
needed, the device begins its transition to the higher sup-
ply range (VCC to SVSS) for the large signals. To ensure a
seamless transition between the low and high supply
ranges, both of the lower transistors are on so that:
ILOAD = IN1 + IN2
As the output signal continues to increase, the transi-
tion to the high supply is complete. The device then
operates in the higher supply range, where the opera-
tion of the device is identical to a traditional dual-sup-
ply Class AB amplifier where:
ILOAD = IN2
During operation, the output common-mode voltage of
the MAX9730 adjusts dynamically as the device transi-
tions between supply ranges.
Figure 1. Class G Supply Transition
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
8 _______________________________________________________________________________________
Utilizing a Class G output stage with an inverting
charge pump allows the MAX9730 to realize a 2.4W
output power with a 5V supply.
The theoretical best efficiency of a linear amplifier is
78%; however, that efficiency is only exhibited at peak
output powers. Under normal operating levels (typical
music reproduction levels), efficiency falls below 30%,
whereas the MAX9730 still exhibits 50% efficiency
under the same conditions.
Inverting Charge Pump
The MAX9730 features an integrated charge pump with
an inverted supply rail that can supply greater than
700mA over the positive 2.7V to 5.5V supply range. In
the case of the MAX9730, the charge pump generates
the negative supply rail (PVSS) needed to create the
higher supply range, which allows the output of the
device to operate over a greater dynamic range as the
battery supply collapses over time.
Shutdown Mode
The MAX9730 has a shutdown mode that reduces
power consumption and extends battery life. Driving
SHDN low places the MAX9730 in a low-power (0.3µA)
shutdown mode. Connect SHDN to VCC for normal
operation.
Click-and-Pop Suppression
The MAX9730 Class G amplifier features Maxim’s com-
prehensive, industry-leading click-and-pop suppres-
sion. During startup, the click-and-pop suppression
circuitry eliminates any audible transient sources inter-
nal to the device.
Applications Information
Differential Input Amplifier
The MAX9730 features a differential input configuration,
making the device compatible with many CODECs, and
offering improved noise immunity over a single-ended
input amplifier. In devices such as PCs, noisy digital
signals can be picked up by the amplifier’s input
traces. The signals appear at the amplifiers’ inputs as
common-mode noise. A differential input amplifier
amplifies the difference of the two inputs, and signals
common to both inputs are canceled out. When config-
ured for differential inputs, the voltage gain of the
MAX9730 is set by:
where AVis the desired voltage gain in dB. RIN+ should
be equal to RIN- and RFB+ should be equal to RFB-. The
Class G output stage has a fixed gain of 4V/V (12dB). Any
gain or attenuation set by the external input stage resistors
will add to or subtract from this fixed gain. See Figure 3.
AR
RdB
VFB
IN
=×
⎛
⎝
⎜
⎞
⎠
⎟
⎡
⎣
⎢
⎢
⎤
⎦
⎥
⎥
()
20 4log
_
_
MAX9730
EFFICIENCY vs. CLASS AB
MAX9730 fig02
OUTPUT POWER (W)
EFFICIENCY (%)
1.51.00.5
10
20
30
40
50
60
70
80
90
100
0
0 2.0
MAX9730
TRADITIONAL CLASS AB
MAX9730
+
IN+
FB+
RIN+
RIN-
CIN-
CIN-
IN-
FB-
-
CLASS G
OUTPUT
STAGE
RFB+
RFB-
Figure 2. MAX9730 Efficiency vs. Class AB Efficiency vs.
Class D Efficiency
Figure 3. Gain Setting
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
_______________________________________________________________________________________ 9
In differential input configurations, the common-mode
rejection ratio (CMRR) is primarily limited by the exter-
nal resistor and capacitor matching. Ideally, to achieve
the highest possible CMRR, the following external com-
ponents should be selected where:
and
Component Selection
Input-Coupling Capacitor
The AC-coupling capacitors (CIN_) and input resistors
(RIN_) form highpass filters that remove any DC bias from
an input signal (see the
Typical Application
Circuit/Functional Diagram
). CIN_ blocks DC voltages
from the amplifier. The -3dB point of the highpass filter,
assuming zero source impedance due to the input signal
source, is given by:
Choose CIN so that f-3dB is well below the lowest fre-
quency of interest. Setting f-3dB too high affects the
amplifier’s low frequency response. Use capacitors with
low-voltage coefficient dielectrics. Aluminum electrolytic,
tantalum, or film dielectric capacitors are good choices
for AC-coupling capacitors. Capacitors with high-voltage
coefficients, such as ceramics (non-C0G dielectrics),
can result in increased distortion at low frequencies.
Charge-Pump Capacitor Selection
Use capacitors with an ESR less than 50mΩfor opti-
mum performance. Low-ESR ceramic capacitors mini-
mize the output resistance of the charge pump. For
best performance over the extended temperature
range, select capacitors with an X7R dielectric.
Flying Capacitor (C1)
The value of the flying capacitor (C1) affects the load
regulation and output resistance of the charge pump. A
C1 value that is too small degrades the device’s ability
to provide sufficient current drive. Increasing the value
of C1 improves load regulation and reduces the charge-
pump output resistance to an extent. Above 1µF, the on-
resistance of the switches and the ESR of C1 and C2
dominate. A 4.7µF capacitor is recommended.
Hold Capacitor (C2)
The output capacitor value and ESR directly affect the
ripple at PVSS. Increasing C2 reduces output ripple.
Likewise, decreasing the ESR of C2 reduces both rip-
ple and output resistance. A 10µF capacitor is recom-
mended.
Charge-Pump Frequency Set Resistor (R
FS
)
The charge pump operates in two modes. When the
charge pump is loaded below 100mA, it operates in a
slow mode where the oscillation frequency is reduced
to 1/4 of its normal operating frequency. Once loaded,
the charge-pump oscillation frequency returns to nor-
mal operation. In applications where the design may be
sensitive to the operating charge-pump oscillation fre-
quency, the value of the external resistor RFS can be
changed to adjust the charge-pump oscillation fre-
quency (see Figure 4).
fRC
Hz
dB IN IN
−=××
()
3
1
2π__
CC
IN IN+=−
R
R
R
R
FB
IN
FB
IN
+
+
=−
−
CHARGE-PUMP OSCILLATION
FREQUENCY vs. RFS
MAX9730 fig04
RFS (kΩ)
CHARGE-PUMP OSCILLATION FREQUENCY (kHz)
12510075
250
300
350
400
450
500
550
600
200
50 150
ILOAD > 100mA
Figure 4. Charge-Pump Oscillation Frequency vs. RFS
MAX9730
Thermal Considerations
Class G amplifiers provide much better efficiency and
thermal performance than a comparable Class AB
amplifier. However, the system’s thermal performance
must be considered with realistic expectations and
include consideration of many parameters. This section
examines Class G amplifiers using general examples to
illustrate good design practices.
TQFN Considerations
The exposed pad is the primary route of keeping heat
away from the IC. With a bottom-side exposed pad, the
PCB and its copper become the primary heatsink for
the Class G amplifier. Solder the exposed pad to a
large copper polygon that is connected to the ground
plane.
The copper polygon to which the exposed pad is
attached should have multiple vias to the opposite side
of the PCB, where they connect to GND. Make this
polygon as large as possible within the system’s con-
straints.
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, PCB techniques,
bump-pad layout, and recommended reflow tempera-
ture profile, as well as the latest information on reliability
testing results, go to the Maxim website at www.maxim-
ic.com/ucsp for the application note,
UCSP—A Wafer-
Level Chip-Scale Package
.
2.4W, Single-Supply, Class G Power Amplifier
10 ______________________________________________________________________________________
Typical Application Circuit/Functional Diagram
MAX9730
+
IN+
FB+
1 (B2)
0.1μF
4 (A3)
14, 22
(D1, D5)
RIN-
10kΩ
VCC
RIN-
10kΩ
CIN
1μF
CIN
1μF
IN-
20 (D2)
16 (D4)
FB-
OUT+
13 (C5)
( ) UCSP PACKAGE
DEVICE SHOWN WITH AV = 12dB
*SYSTEM-LEVEL REQUIREMENT TYPICALLY 10μF
FS
OUT-
10 (B5)
7 (A4)
9 (A5)
12 (B4)
18 (D3) 27 (A1) 26 (B1) 3 (A2) 24 (C1) 15, 21
(C2, C4)
-
CLASS G
OUTPUT
STAGE
CHARGE
PUMP
RFB+
10kΩ
RFB-
10kΩ
SHDN
CPGND PVSS SVSS
C1N C1P
C2
10μF
RFS
100kΩ
GND
CPVDD
C1
4.7μF
VDD
*
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
______________________________________________________________________________________ 11
Pin Configurations
28
27
26
25
24
23
22
8
9
10
11
12
13
14
15
16
17
18
19
20
21
7
6
EP*
*EXPOSED PAD.
5
4
3
2
1
+
MAX9730
THIN QFN
TOP VIEW
N.C.
SHDN
C1P
CPVDD
N.C.
N.C.
FB-
N.C.
CPGND
C1N
N.C.
PVSS
N.C.
VCC
SVSS
OUT+
N.C.
GND
N.C.
OUT-
SVSS
VCC
FS
FB+
N.C.
IN+
IN-
N.C.
MAX9730
TOP VIEW
(BUMP SIDE DOWN)
UCSP
CPVDD
C1P IN-
CPGND
1
A
B
D
23 5
C
FB-
SHDN IN+
C1N FB+
SVSS FS
PVSS SVSS
GND
OUT+ VCC
VCC OUT-
4
Chip Information
PROCESS: BiCMOS
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
12 ______________________________________________________________________________________
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
24L QFN THIN.EPS
PACKAGE OUTLINE,
21-0139
2
1
E
12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
______________________________________________________________________________________ 13
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
PACKAGE OUTLINE,
21-0139
2
2
E
12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm
MAX9730
2.4W, Single-Supply, Class G Power Amplifier
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
14
____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
5x4 UCSP.EPS
ENGLISH • ???? • ??? • ???
WHAT'S NEW
PRODUCTS
SOLUTIONS
DESIGN
APPNOTES
SUPPORT
BUY
COMPANY
MEMBERS
MAX9730
Part Number Table
Notes:
See the MAX9730 QuickView Data Sheet for further information on this product family or download the
MAX9730 full data sheet (PDF, 292kB).
1.
Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.2.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually
within one business day.
3.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: See
full data sheet or Part Naming Conventions.
4.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the
product uses.
5.
Part Number
Free
Sample
Buy
Direct
Package:
TYPE PINS SIZE
DRAWING CODE/VAR *
Temp
RoHS/Lead-Free?
Materials Analysis
MAX9730ETI+
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9730ETI+T
THIN QFN;28 pin;4X4X0.8mm
Dwg: 21-0139E (PDF)
Use pkgcode/variation: T2844+1*
-40C to +85C
RoHS/Lead-Free: Yes
Materials Analysis
MAX9730EBP+
-40C to +85C
RoHS/Lead-Free: Yes
MAX9730EBP+T
-40C to +85C
RoHS/Lead-Free: Yes
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